Sprocket device



Patented Oct. 29, 1946 SPROCKET Louis A. McNabb, Glenview, IllL,vassignor to Bell & Howell Company, ChcagoJll., a corporation ofIllinois.

Application June s, 1945, serialno. 598,385`

(o1. v4-24s 14 Claims. l

My invention relates toperforated ilrnA feed sprocket. devices of motionpicture machines, although not limited toA this use alone, and hasparticular; relation to suchdevices involving a sprocket having:sprocket teeth onlyV at one end thereon' Objet-:tsmc the inventionreside in theY provisionl of a novel and effective guide means forreleasably retaininga perforated strip engaged onafsprocket, whichprevents punching or embossing of'the strip byl reason of; the guidebeing pressed against the outer face of the strip While the-strip rideson to-p of theteeth of thesprocket, which isconvenient in engagingthestrip on and removing the same rromvthe sprocket, and which. isinherently of an unobtrusive and simple appearance.

The invention Will bebetter understoody byv ref-` erence to theaccompanying drawing forming a part hereof andY in Which- Figures 1 and.2 are sectional views of a sprocke. et device embodying my inventionandtaken on the line l-i of Figure 3, these views sho-Wing partsindifferent' positions;

Figure 3 is an. endl elevation of the sprocket device; and

Figure 4 is a view in elevation similar to that.

of Figure 3 and having parts. ofthe structure. shown in section;

Referring to the drawing, l4 designates a sup-A portv or `frame which isprovided withA a circular recess 2, andan annular support-member 3e isse cured in this recess and forms a part off. the support or'frame. SeeFiguresv l and 2; The mem.-V ber 3 is counterbored inwardlyl from theouter face thereof to form aoircular recess II.v

A spindle 5y is rotatably mounted on; the support I- through the medium.of a bushing 6., and this; spindlev is disposed concentrically oi the.re-

cess- 4 and projects through this recess` and out-- wardly of thesupport. Avlm sprocket; l is,se:

cured on the projecting. .end of the spindle 5 by.

. means of. a set screw 8, the sprocket being dis` posed in projectingrelation with the sllpllortA and being rotatable with the spindle'whichis driven in a usual manner.

A strip retaining guide 9 of circular disk form is disposed inY theregion otk the inner endof the sprocket 'l and extends betweenv thesupport member 3 and the sprocket l transversely of and across thesprocket aXis and is provided with a central bore il through whichthespindle 5. and an inwardly projecting hub I2 of the sprocket, passes.The guide .111sy mounted in the recess. 4f

for 'movement axially of, the sprocket. 1, and. a,y

stopV ring I3 is secured onthe outer face of the supportv member 3 inconcentric relation therewith and. overliesthe marginal portion of therecess i! and is thus engageable. by the marginal portion of, the guideil to limit outward movement of the guide. Rotation of the guide S` isprevented by a guide pinM secured on the support member 3 in parallelrelation with the spindle 5 and. slidably engaging in an aperture l5Vthrough. the guide.

The central portion of the guide 9 is offset outwardly axially of. theguide, as designated at l5, and projects into, an annular channel il inthe inner end, portion of the sprocket lj; this ofiset portion. Hi'affording considerable space between it. and the outer end of thebushing 5. A helical compressionl spring i8 encircles the spindie 5. andhub l2 between the offset portion IS. and the bushing 6 and, isoperative between this oiset portion andbushing to yieldably urge theguide gfaxially of the sprocket 1 and outwardly into engagement withthestop ring I3, as shown in Figure 1,., the guide. being movable, againstthe influence of this spring, inwardly axially of the sprocket into theposition shown* in Figure 2;

The sprocket T is provided with sprocket teeth I9' only inthe region ofits inner end, and the sprocket. is. also provided with a strip edgeengaging shoulder 2l in the region o-f its outer end and" facingtowardits inner end'. A strip 22, such as a motionA picture filmstripprovided with feed perforations 23 is engaged on the sprocket with feed'perforations of the strip engaged on teeth of the sprocket for feedingthe strip, the annular shoulder 2`l being engageable with the opposinged'gevof the strip for laterally guiding the same in one direction, andguide rollers 24 carried on the.

support I' serving to guideY the strip to and from the sprocket, asshown in Figures 3* and 4.

The guide 9 is provided with an arcuate porti'on 2 5' extendingcorrespondingly with the pee riphery of. the sprocket l and the internalsurface Z5 of this portion. provides a guide surface facing radialiy ofandtoward the sprocket axis .vandengageable with the outer face of thestrip 'V22 engaged on, the sprocket to retain the feed perorations of'the strip in engagement with the sprocket teethwh'en the guide 9 ispositioned by the spring i8 and stop. ring` I3. in its strip guidingposition. as` shownV in Figure 1. The outer face 2l of the guide ilimmediately inward of' the surface 2,6, provides a strip edge engagingguide surface facing toward the shoulder 2| of the sprocket andcooperating with this shoulder in laterally guiding the: striptherebetween` when the guide 9 is in its strip guiding position.Movement of the guide 9 inwardly from the position thereof shown inFigure l positions the guide out of strip guiding position as shown inFigure 2 in which position of the guide the strip may be convenientlyengaged on or removed from the sprocket.

The external surface 28 of the arcuate portion 25 of the guide Sprovides a cam surface which is inclined with respect to the sprocketaxis and faces in the direction of the outer end of the sprocket 'i andradially outward of the sprocket axis and is engageable by the opposingedge of the strip 22 as an incident of engaging the strip on thesprocket to actuate the guide out of strip guiding position against theinfluence of the spring I3 and permit engagement of the strip on thesprocket, the springr Iii being comparatively Weak and the fitting ofthe guide 9 with the parts engaged thereby being suiciently loose topermit canting of the guide for this purpose. After the strip is engagedon the sprocket, the spring automatically actuates the guide into stripguiding position. Thus, engagement of the strip on the sprocket is anextremely simple and convenient operation.

Obviously, the portion 25 of the guide cannot press against the outerface of the strip 2.2 while the strip rides on top of the teeth ofthesprocket so that punching or embossing of the strip is prevented.

The outer end of the sprocket 'l is concentrically ccunterbored, asdesignated at 29, and a push plunger head 3l, at the outer end of thesprocket, is mounted within this counterbore for reciprocation axiallyof the sprocket and is accessible for manual depression as by a personsfinger 32 as shown in Figure 2. Three plunger rods 33 extend within thesprocket 1 and are arranged in parallelism with and spaced about thesprocket axis exteriorly of the spindle and are mounted forreciprocation axially of the sprocket in bores 3d through the sprocket.See Figures 1, 2 and 4.

The outer ends of the rods 33 are secured with the plunger head 3| andthe inner ends of these rods are secured with a ring 35 slidably mountedin the annular channel l1 of the sprocket and disposed outwardly of thecentral offset portion i6 of the guide 9 and engageable axially of thesprocket inwardly against the offset portion I6, this assembly forming apush plunger device mounted for reciprocation within and axially oi thesprocket and operative on the guide 9 axially of the sprocket foractuating the guide inwardly out of strip guiding position by manualdepression of the plunger head 3l as shown in Figure 2, thus providingfor conveniently positioning the guide out of strip guiding position forremoving the strip 22 from the sprocket'J 1 and, if desired, forengaging the strip on the sprocket. A helical compression spring 3eencircles the extreme outer end of the spindle and is arranged withinopposing recesses 3'! and 38 respectively in the sprocket l and plungerhead 3l, and is operative between the sprocket and plunger head toyieldably urge the push plunger device outwardly, as shown in Figure 1.,independently of the spring i8, thus not necessitating the spring I8being sufficiently strong to actuate the push plunger device outwardly.

While I have thus described my invention, I do not wish to be limited tothe precise details described, as changes may be readily made withoutdeparting from the spirit of my invention,

but having thus described my invention, I claim as new and desire tosecure by Letters Patent the following:

1. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth in the region of its innerv end, a stripretaining guide disposed in ie region of the inner end of said sprocketand provided with a guide surface facing radially of and toward thesprocket axis and engageable with the 'outer face of a perforated stripengaged on said sprocket, and said guide being mounted for movementaxially of said sprocket into and out of strip guiding position.

2. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth in the region of its inner end and with astrip edge engaging annular shoulder in the region of its outer end andfacing toward its inner end, a strip retaining guide disposed in theregion of the inner end of said sprocket and provided with a guidesurface facing radially of and toward the sprocket axis engageable withthe outer face of a perforated strip engaged on said sprocket and with asecond strip edge engaging guide surface facing toward said shoulder,and said guide being mounted for movement axially of said sprocket intoand out of strip guiding position.

3. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth only in the region oiI its inner end andwith a strip engaging annular shoulder in the region of its outer endand facing toward its inner end, a strip retaining guide disposed in theregion of the inner end of said sprocket and provided with aguidesurface facing radially of and toward .the sprocket axis and engageablewith the outer face of a perforated strip engaged on said sprocket andprovided with a strip edge engaging guide surface facing toward saidshoulder, said guide being mounted for movement axially of said sprocketinto and out of strip guiding position and being yieldably urged intostrip guiding position,.and stop means limiting movement of said guideinto strip guiding position.

4. In a sprocket device, the combination with a support and a spindlemounted thereon and projecting therefrom, of a revoluble sprocketcarried on said spindle in projecting relation With said support andprovided with sprocket -teeth in the region of its inner end, a stripretaining guide disposed in the region of the inner end of said sprocketand extending between said support and sprocket transversely of andacross the sprocket axis and provided with an opening through which saidspindle passes and provided with a guide surface facing radially of andtoward the sprocket axis and engageable with the outer face of aperforated strip engaged on said sprocket, said guide being mounted formovement axially of said sprocket into and out of strip guidingposition, spring means operative to yieldably urge said guide into stripguiding position, and stop means limiting movement of said guide intostrip guiding position.

5. In a sprocket device, the combination with a support provided with .arecessv and a spindle mountedcn said support and projecting therefromcentrally of said recess, of a revoluble sprocket carried on saidspindle in projecting relation .with said support. and provided withsprocket. teeth in the region. of itsv inner end, a strip. retainingguide disposed in the region ofl the inner end of said sprocket andextending between. said' support and-sprocket. transversely of andacross .the sprocket axis. and provided' with an opening through whichsaid spindle passes and provided. with a guide surface facing radiallypression spring encircling said spindle and opera-` tive to yieldablyurge said guide into strip. guiding position, and stop means limitingmovement of said guide into strip guiding position.

6. In. asprocket device, the combination with a support provided with arecess and a spindle mounted on said support and projecting therefromcentrally of said recess, of a revoluble sprocket carried on saidispindle in projecting relation with said support .and provided withsprocket teeth` only in the region of its inner end and provided with astripengaging annular shoulder in the region ofr its outer end andfacing toward its inner end, a strip retaining guide disposed in theregion of .the inner end of said sprocket and extendingbetweeny saidsupport and sprocket -transversely of .and across the sprocket axis andprovided with an opening throughwhi'ch saidspindle passes and providedwith 'a guide surface facing radially of and toward .the sprocket axisand engageable with the outer face of a perforated strip engaged on saidsprocket and provided with a strip edge engaging guide surface `facingtoward said shoulder, said guide being mounted in said recess formovement axially of said sprocket into and out of vstrip guidingposition, a helical compression spring encircling said spindle andoperative between said support and guide to yieldably urge said guideinto strip guiding position, `and a stop ring secured on said supportand overlying the marginal portion of said recess and eng-ageable bysaid guide to limit movement of said guide into strip guiding position.

'7. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth in the region of the inner end thereof, astrip retaining guide disposed in .the regi-on of the inner end of saidsprocket and provided with a guide surface facing radially of and towardthe sprocket axis and engageable with .the outer face of a perforatedstrip engaged on said sprocket, said guide being mounted for movementaxially of said sprocket into and out of strip guiding position, andmeans for positioning said guide in and out of strip guiding. positioncomprising an actuating device mounted for reciprocation within andaxially of said sprocket .and accessible for manual .actuation at theouter end of said sprocket.

8. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth in the region of the inner end thereof, astrip retaining guide disposed in the region of the inner end of saidsprocket and provided with a guide surface facing radially of and towardthe sprocket axis and engageable with -the outer face of a perforatedstrip engaged on said sprocket, said guide being mounted for movementaxially of said sprocket into` and out i. of strip guiding, position,spring means yie'lgdably urging: said guide into strip guiding position,and a push plunger devicev mountedfor reciprocation within and axiallyof said sprocket. and operative on said guide axially of said, sprocket.forr actuating said guide out'Y of strip` guiding position andaccessible. for manual i depression at the. outer end. of said sprocket.

9. In asprocket device, the combination. with a support and a spindlemounted thereon and sp-rocken said guide being mounted for movementaxially of said sprocket into and out oi strip guiding position, springmeans operative to yieldably urge said guide into strip guidingposition, andv a push plunger device mounted for reciprocation with-inand axially of said sprocket and operative on said guide axially of saidsprocket for actuating said guide out of strip.`

guiding position andY comprising a plurality of plunger rods extendingwithin said sprocket and arranged in parallelism with and spaced aboutthe sprocket axis exteriorly of said spindle and a head at the outer endof said sprocket and accessible for manual depression and operative onsaid rods.

10. In a sprocket device, the combination with a support provided with arecessand a spindle mounted on said support and projecting therefromcentrally of Ysaid recess, of a revoluble sprocket carried on saidspindle in projecting relation with said support and provided withsprocket teeth only in the region of its inner end and provided with astrip engaging annular v shoulder in the region of its outer end andfacing toward its inner end, a strip retaining guide disposed in theregion of the inner end of said sprocket and extending between saidsupport and sprocket transversely of and across the sprocket axis andprovided with an opening through which said spindle passes and providedwith a guide surface facing radially of and toward the sprocket axisand` engageable with the outer face of a perforated strip engaged onsaid sprocket and provided with a strip edge engaging guide surfacefacing to-ward said shoulder, said guide being mounted in said recessfor movement axially of said sprocket into and out of strip guidingposition, spring means operative to yieldably urge said guide into stripguiding position, stop means limiting movement of said guide into Stripguiding position, and a push plunger device mounted for reciprocationwithin and axially of said sprocket and operative on said guide axiallyof said sprocket for actuating said guide out of strip guiding positioncomprising a plurality of plunger rods extending Within said sprocketand arranged in parallelism with and spaced about the sprocket axisexteriorly of said spindle and a head at the outer end of said sprocketand accessiblefor .manual depression and operative on said rods.

11. In a sprocket device, the combination with a support, of a revolublesprocket carried therewith in projecting relation with the same andprovided with sprocket teeth in the region of its inner end, a stripretaining guide disposed in the region of the inner end of said sprocketand provided with a guide surface facing radially of and toward thesprocket axis and engageable with tlie outer face of a perforated stripengaged on said sprocket, said guide being mounted for move; mentaxially of said sprocket i-nto and out of strip guiding position andbeing yieldably urged into strip guiding position, stop means limitingmovement of said guide into strip guiding position, and said guide beingfurther provided with a cam surface disposed radially of the sprocketoutwardly of said guide surface and inclined with respect to thesprocket axis and facing in the direction of the outer end of saidsprocket and radially outward of the sprocket axis and engage able bythe opposing edge of said strip as an incident of engaging said strip onsaid sprocket to actuate said guide out of strip guiding position.

12. In a sprocket device, the combination recited in claim 3 and furthercharacterized in combination in that said guide is further provided witha cam surface disposed radially of the sprocket axis outwardly of saidrst mentioned guide surface and inclined with respect to the sprocketaxis and facing in thel direction of the outer end of said sprocket andradially outward of the sprocket axis and engagea'ble by the opposingedge of said strip as an incident of engaging said strip on saidsprocket to actuate said guide out of strip guiding position.

13. In a sprocket device, the combination recited in claim 8 and furthercharacterized in combination in that said guide is further provided witha cam surface disposed radially of the sprocket axis outwardly of saidguide surface and inclined with respect to the sprocket axis and facingin the direction of the outer end of said sprocket and radially outwardof the sprocket axis and engageable by the opposing edge of said stripas an incident of engaging saidstrip on said sprocket'to actuate saidguide out of strip guiding position, and that a second spring meansvyieldably urges said push plunger device in the direction correspondingwith movement of said guide into strip guiding position.

14. In a sprocket device, the combination recited in claim l0 andfurther characterized in combination in that said guide is furtherprovided with a cam surface disposed radially of the sprocket axisoutwardly of said rst mentioned guide surface and inclined with respectto the sprocket axis and facing in the direction of the outer end ofsaid sprocket and radially outward of the sprocket axis and engageableby the opposing edge o-f said strip as an incident of engaging saidstrip on said sprocket to actuate said guide out of strip guidingposition, and that a second spring means yieldably urges said pushplunger device in the direction corresponding with movement of saidguide into strip guiding position.

LOUIS A. MCNABB.

